The way I save my left over's for my stash is I find some nice boxes that are about three in deep, and then for most quilts you need strip cut at 2 1/2 to 3 1/2 inch so I just go ahead and cut the strips out of the left over fabric and mark the box as to what colors and size is in the box. The other thing if you have 2 1/2 strips cut already then you need a binding you can just get in the box and see what you have that you can use for that too. I also found that so many quilts that I have made the strip I want are right there in the box and dont have to cut them, you can also buy the see through boxes at the store and you can always see right away what you have in them. It is great for patch work quits.
hope this helps.
Jazzy